My daughter suspects that her children unduly influenced her husband to leave his entire estate to them, attempting to disinherit her. She is too upset to take the matter to court. Can I do it for her?
No. Only a person who has a financial interest in the estate can file a will contest. This usually means only the persons named in the will and anyone who would have inherited if the person had died without a will. Since you do not qualify under either scenario you can not file the contest for her (you are not named in the will and would not have been an intestate heir); she has to do it herself. Note that if she chooses not to file the contest she can still renounce the will and claim her elective share.
There is a time limit for filing a will contest which varies by state law. If she is uncertain as to whether she wants to take action, she should at least research the state’s specific law to find out how long she has to make up her mind.